The present invention relates, in general, to electronic sensors and, more particularly, to sensing transducers in which the metal interconnections between the transducer and external control circuitry are isolated from any harsh media to be sensed by the transducer.
A common type of electronic sensing transducer is a pressure sensor. As pressure sensors become more wide-spread in use, there is a need for sensing the pressure of an increasing variety of media. Such media include what are known as "harsh" media, which typically degrade certain components of the sensor that come in contact with the harsh media. Some examples of harsh media include polar and non-polar solvents, salt water, acids, and bases.
A significant problem in sensing the pressure of a harsh media is that the media itself can adversely affect certain components of the pressure sensor or its package. For example, some organic media can cause swelling or dissolution of plastic components, while some ionic media can permeate through portions of a sensor package and corrode metal components therein or etch exposed silicon surfaces. Accordingly, there is a need for a pressure sensor package that is more resistant to the adverse effects of harsh media, such as swelling or dissolution by organic solvents, metallic corrosion by ionic solutions, or etching of exposed silicon surfaces by alkaline ionic solutions.